DIAGNOSIS; Confusing Confusion

By LISA SANDERS, M.D.

Published: December 7, 2008

1. SYMPTOMS

The middle-aged man writhed on the gurney in the E.R. His eyes were squeezed shut. Low moans emerged from his parched lips. His sister and brother -- the only members of his large Polynesian family who lived here in Portland, Ore. -- tried to comfort him, but worry was etched deeply into their faces. Dr. David Peel, the emergency-room doctor at Providence Portland Medical Center, was also worried. This 53-year-old man had a fever and excruciating pain in his back. One leg was weak and he was confused. But the scariest part of all was that the man had been discharged from this hospital just three days earlier after being treated for the exact same thing.

Peel quickly reviewed the records of that first weeklong stay in the hospital. The patient, a smoker, had a history of diabetes and high blood pressure. He came in confused and with a fever. During that admission, the medical team thought he had an infection in his brain, an encephalitis. His white-blood-cell count was high, which was consistent with an infection, and his spinal fluid was abnormal, suggesting inflammation. In addition, the amount of sodium in his blood -- an essential mineral and one that is tightly regulated by the brain and the kidneys -- was dangerously low, a condition known as hyponatremia. Infections can cause low sodium. So can severe vomiting and diarrhea. And both the encephalitis and the hyponatremia can cause confusion. The team put the patient on powerful antibiotics and was replacing the missing sodium. Treat both, the doctors thought, and the confusion should improve. But it didn't. His fever went down; his sodium went up. But his confusion remained unchanged. He still didn't know where he was or why he was there.

2. INVESTIGATION

That's when the team consulted Dr. David Gilbert, one of the most respected infectious disease doctors in the area. Gilbert talked with the patient's family about the days and weeks before the man came to the hospital. A month earlier, the three siblings traveled to California, where the rest of their large extended family lived, for their annual luau. A few days after returning, their brother started to complain about a pain in his back. They weren't sure if he hurt it at the party or on the job -- he was a mason -- but the pain quickly became severe enough to keep him out of work. He also complained of some nausea and diarrhea. He told them he felt weak, tired. And then, suddenly, he stopped making sense. His speech became slurred and rambling. That's when they took him to the hospital.

Gilbert agreed this was probably an infection in the brain. They had looked for the most common causes of encephalitis -- like herpes -- without success, so Gilbert suggested they look for some of the more unusual infectious agents. Enterovirus was a common cause of nausea and vomiting and sometimes encephalitis. And the patient had recently been to California, so California encephalitis, an unusual mosquito-borne infection, was a possibility. But Gilbert was most concerned about a different mosquito-borne infection, the West Nile virus, which had been moving westward since its first epidemic in New York City in 1999. Two weeks earlier, two birds tested positive for the virus on the outskirts of Portland. Could this patient be the first case of the season?

They would need to look for each of these viruses in the spinal fluid. And they should stop all the antibiotics he was now getting. If he had a virus, they wouldn't help. If he had a bacterial infection, the antibioitcs would make finding it even more difficult, and identifying the bug was essential to ensuring the infection was properly treated.

And then they waited. Five days later, the patient started making sense: he was able to tell the team that he was in the hospital, and he knew what year it was. The family was ecstatic. The doctors still didn't know what he had, but they were relieved that he was getting better. A couple of days later, he was still a little confused, but his family persuaded the doctors to send him home.

But now, just three days after his discharge, he had returned. His back pain was excruciating and radiated down his left leg, making it too painful to move. He had a fever. His sodium was even lower than it was a week earlier. His white-blood-cell count was high, and his red-blood-cell count, which had been normal, had dropped precipitously. All the tests sent out during his last hospital stay came back negative. He was deathly ill, but it was clear to Peel that no one had any idea why.

The combination of fever, back pain and weakness worried Peel. Perhaps the infection was in his spinal column. He sent the patient to get an M.R.I. The radiologist called as soon as the scan was done. There was no abscess on the spinal cord, but the patient's aorta had weakened and the pressure of the blood flow had caused the tube to bulge like a worn garden hose. He was also concerned that this weak spot had sprung a leak. He could see blood outside the vessel.

This was an emergency. A ruptured aorta, even when it happens in the hospital, has a mortality rate of 50 percent. Peel called the vascular surgeon, and the patient was rushed to the operating room.

The left side of his abdominal cavity was filled with blood, and parts of the normally thick tube of the aorta were in tatters. The surgeon quickly replaced the shredded portion of the aorta and sent the dissected bits to the lab. Under the microscope, it became clear what had caused all of this man's symptoms. The tissue had been invaded by a bacterium -- an unusual type of salmonella, one usually found in uncooked pork. This bug -- salmonella choleraesuis (from Latin, meaning the gut of the pig) -- had wreaked havoc. Like the more familiar salmonella infection, picked up from eggs and other contaminated foods, this one causes nausea, vomiting and diarrhea. But salmonella can do much much more: under the right circumstances, it can get out of the digestive system and invade virtually any part of the body. This type of salmonella has a particular affinity for the blood vessels. It had invaded the patient's aorta and clouded his brain.

3. RESOLUTION

The brief dose of antibiotics during his first hospital stay had tamed the infection temporarily -- that's why he was able to go home -- but the extensive destruction of the aorta made a lengthy course of antibiotics and the surgical repair imperative. With the infective agent finally identified, the patient was started again on antibiotics.

When David Gilbert came into the hospital the next morning, he was surprised to find that his patient from a few days before was again listed among the patients in the I.C.U. and even more surprised to see what had made the man so sick.

He sought out the family. Did they have any idea where this man may have been exposed to uncooked or undercooked pork? And why hadn't anyone else gotten sick? That was easy, the sister told him. The patient always prepared the pig for the family luau. It was his specialty, and no one else was allowed to touch, much less taste, the meat until he served it.

With the infection under control, the patient recovered rapidly. Three days after the operation, Gilbert found him sitting up in bed, laughing and chatting with his family. This year, his family skipped the roasted pig at the luau, the patient told me recently. Maybe next year they'll try again. Or maybe not.